(1) Field of the Invention
This invention relates to apparatus for treating fluids with radiation, and particularly relates to a portable personal water purification system.
(2) Description of Related Art
A portable water purification system that can rapidly eliminate microbiological contaminants from suspect water sources is attractive for both military and commercial sectors. Such a system enables soldiers, outdoorsmen, and other persons who lack access to clean water to reduce or eliminate the need to transport water for the trip. The requirements for such a system include: low cost, light weight, low power consumption, ruggedness, high water flow rate, durability, and, of course, ability to produce water meeting drinking standards such as the Tri-service standard described in TB Med 577. Current water purification technologies suffer from limitations that have impeded their implementation in a low-cost, portable configuration. We address key barriers to the development of such a portable water purification system through the use of a novel, low-power, flexible ultraviolet (UV) light source for rapid disinfection of microbiological contaminants including bacteria, protozoan cysts, and viruses.
Many technologies for water purification have been developed, including mechanical filtration, distillation, reverse osmosis, UV disinfection, chlorination, and ozonation. Each of these technologies suffers from major limitations that have diminished their adoption for portable water purification. In many cases, the technologies effective to meet the requirements in some areas outlined above are severely limited for meeting other requirements. For example, reverse osmosis (RO), is very effective at removal of pathogens in water, is light weight and requires no power consumption. However, reverse osmosis is an extremely slow process, can be costly, and is not rugged in that its effectiveness can be compromised by membrane rupture.
We present a novel, low-power, water purification system that incorporates a flexible microdischarge array as a source for UV disinfection. Such arrays are attractive as a large-area flexible sheet UV light source for germicidal applications due to their ruggedness, conformability, low manufacturing cost, and efficiency. In addition, they can be tailored to deliver the exact spectrum required for disinfection (200-300 nm with a peak at 254 nm) and can operate using nontoxic alternatives to mercury, such as XeI. We integrate the flexible microdischarge array into a water purification system that will enable removal of bacteria to 6 logs, protozoan cysts to 3 logs, and viruses to 4 logs. The disinfection system is lightweight (<18 oz.), performs at high speed (>1 liter/min), and produces at least 150 liters of potable water prior to maintenance. Finally, we incorporate mechanical prefilters to assist in removal of turbidity and toxic contaminants.